With the increasing use of computers, electronic communication has become more popular. The great flexibility of Transmission Control Protocol/Internet Protocol (TCP/IP) has led to its worldwide acceptance as the basic Internet and intranet communications protocol. TCP/IP allows information to be sent from one computer to another through a variety of intermediate computers and separate networks before it reaches its intended destination. Typically, in fact, information is transmitted in this manner, particularly over the Internet. This method of transmission, through intermediate computers and separate networks, makes it possible for a third party to interfere with communications. A third party can interfere with transmitted Internet communication in several ways. A third party can “eavesdrop;” in other words, the information is not changed but its privacy is compromised. For example, an eavesdropper can obtain a credit card number, or record sensitive or classified information, and then pass on the original message to the intended recipient. Additionally, a third party can change or replace the information and then send it to the intended recipient.
Many sensitive personal and business communications transmitted over the Internet require precautions that address privacy concerns. Current so-called “secure” transmission techniques use various encryption technologies to achieve this goal. Public-key cryptography is one well-established technique that addresses some of the privacy concerns in electronic communication. The sender of the communication encrypts the communication using an encryption key. The recipient of the encrypted communication then decrypts the information using a decryption key. Only recipients who have a decryption key can decrypt the electronic communication and read its contents.
Although encryption provides a level of protection against third party interference with the electronic communication, an unauthorized recipient can still have access to the information contained in the communication if the recipient can decrypt the information. Consequently, there is a need to protect the content of an electronic communication should an unauthorized user gain access to the electronic communication and subsequently attempt to decrypt the electronic communication.